Raillard Mathieu, Mosing Martina, Raisis Anthea, Auckburally Adam, Beaumont Georgina, Downing Frances, Heselton Charlotte, MacFarlane Paul, Portier Karine, Robertson Josephine, Soares Joao Henrique Neves, Steblaj Barbara, Wringe Elliot, Levionnois Olivier L
School of Veterinary Medicine, College of Environmental and Life Sciences, Murdoch University, Murdoch, WA, Australia.
Anaesthesiology and Perioperative Intensive Care, Clinical Department for Small Animals and Horses, Veterinary University Vienna, Vienna, Austria.
Front Vet Sci. 2024 Nov 28;11:1490494. doi: 10.3389/fvets.2024.1490494. eCollection 2024.
In clinical practice, evaluating dynamic compliance of the respiratory system (C) could provide valuable insights into respiratory mechanics. Reference values of C based on body weight have been reported, but various factors may affect them and the evidence is scanty. This study aimed to establish a reference interval for C and identify associated variables.
Data were collected from 515 client-owned dogs requiring anesthesia, excluding those with lower airway disease. The dogs were anesthetized, the tracheas intubated, and lungs ventilated at clinicians' discretion across 11 centers in six countries, with no restrictions on anesthesia protocols or ventilation settings, except avoiding inspiratory pauses. Three C measurements from three consecutive breaths per dog were recorded using a standardized form, which also documented factors affecting C identified through literature and an online survey. Various spirometry technologies were used. The substantial variance in C measurements led to a comprehensive analysis using a multiple linear regression model. Multicollinearity (variables highly correlated with each other) was addressed by investigating, transforming, or excluding factors. Initial simple linear regression assessed each variable's individual effect on C, followed by a multiple linear regression model constructed via stepwise forward selection and backward elimination.
The best-fitting model identified a linear relationship between C and body mass when the following conditions were met: high BCS (Body Condition Score), orotracheal tubes <7% smaller than predicted, the use of a D-lite flow sensor, and the absence of a high FIO2 (>80%) exposure for more than 10 minutes before C measurement. In cases where these conditions were not met, additional factors needed to be incorporated into the model. Low (1/9, 2/9, 3/9) and medium (4/9, 5/9) BCS, an orotracheal tube of the predicted size or larger and longer inspiratory times were associated with increased C. The use of alternative spirometry sensors, including Ped-lite, or prolonged exposure to high FIO levels resulted in decreased C.
Establishing a reference interval for C proved challenging. A single reference interval may be misleading or unhelpful in clinical practice. Nevertheless, this study offers valuable insights into the factors affecting C in healthy anesthetized dogs, which should be considered in clinical assessments.
在临床实践中，评估呼吸系统的动态顺应性（C）可为呼吸力学提供有价值的见解。已报道了基于体重的C的参考值，但各种因素可能会影响这些值，且相关证据不足。本研究旨在建立C的参考区间并确定相关变量。
收集了515只需要麻醉的宠物犬的数据，排除患有下呼吸道疾病的犬只。这些犬只在六个国家的11个中心接受麻醉，气管插管，并由临床医生酌情进行肺通气，除避免吸气暂停外，对麻醉方案或通气设置没有限制。使用标准化表格记录每只犬连续三次呼吸的三次C测量值，该表格还记录了通过文献和在线调查确定的影响C的因素。使用了各种肺量计技术。C测量值的巨大差异导致使用多元线性回归模型进行综合分析。通过研究、转换或排除因素来解决多重共线性（彼此高度相关的变量）问题。最初的简单线性回归评估每个变量对C的个体影响，随后通过逐步向前选择和向后排除构建多元线性回归模型。
当满足以下条件时，最佳拟合模型确定了C与体重之间的线性关系：高体况评分（BCS）、口气管导管比预测值小不到7%、使用D-lite流量传感器以及在测量C之前不存在超过10分钟的高FIO2（>80%）暴露。在不满足这些条件的情况下，需要将其他因素纳入模型。低（1/9、2/9、3/9）和中等（4/9、5/9）的BCS、预测尺寸或更大尺寸的口气管导管以及更长的吸气时间与C增加相关。使用包括Ped-lite在内的替代肺量计传感器或长时间暴露于高FIO水平会导致C降低。
为C建立参考区间被证明具有挑战性。单一的参考区间在临床实践中可能会产生误导或毫无帮助。尽管如此，本研究为影响健康麻醉犬C的因素提供了有价值的见解，在临床评估中应予以考虑。
